Generally, since a small number of targeted genes to be detected are included in a targeted sample for gene analysis, direct measurement thereof is not easy. Accordingly, in most experimental tests which detect genes, a gene amplifying process is performed to increase the number of specific targeted genes before the genes are measured.
A polymerase chain reaction (PCR) technique is a representative technique which amplifies genes. The PCR technique forms a reaction solution by mixing a template DNA including a specific base sequence in a sample with polymerases, a primer set, dNTP, magnesium chloride, a buffer, or the like, and the number of genes can be amplified while a temperature of the reaction solution is changed according to thermal-cycling. The thermal-cycling includes three temperature sections, such as a denaturation operation, an annealing operation, and an extension operation, which are sequentially performed. In the PCR technique, the number of genes of a specific base sequence included in a template can be exponentially amplified by chain reaction using polymerases.
Further, a fluorescent material can be used for detecting genes. When the fluorescent material is added into a reaction solution, a fluorescent signal is increased in proportion to the number of genes (i.e., concentration), and thus, the fluorescent signal can be detected to measure the number of genes (i.e., concentration) which is amplified by the PCR.
Meanwhile, recently, PCR chips applied by various methods using micro-chips have been developed to perform a PCR process of amplifying genes at a super high speed and low cost. Further, various heating methods which perform thermal-cycling have been proposed. However, the conventional method has problems such as high power consumption, high manufacturing cost, etc.
In the case of a method in which an external heat source, such as a metal block, a film heater, or the like, contacts an outside of a PCR chip, relatively, heat response is slow, power consumption is high, manufacturing cost is high, and it is difficult to make a small size. Further, since the metal block or film heater cannot secure transparency, an optical path used for measuring a fluorescent signal should be specially designed.
In the case of a method in which a micro-patterned heater is directly installed on a surface of a PCR chip, heat response is fast, power consumption is low, and it is easy to make a small size. However, manufacturing cost is high, and an optical path cannot be secured due to opacity.
Further, in the case of a non-contact heating method using optical irradiation, it is difficult to make a small size because a device for the optical irradiation should be provided separately, and an adsorption material for heating should be included in a reaction solution.
As described above, since the conventional PCR chip includes a heating material for thermal-cycling, there are some problems such as heat response, power consumption, manufacturing cost, miniaturization, securement of an opacity for measuring fluorescence, etc.